I got a few:
The "Zip A Dee Doo Dah" sketch with Alan Arkin...freaking hilarious
Any of the sketches with John Cleese
Lydia the Tattooed Lady
And I love the whole Carol Burnett episode
Bert singing "Some Enchanted Evening" with Connie Stevens

For humor - The banana Boat song from the Harry Belafonte episode.
For a touching moment - Bein' Green from the Peter Sellers episode.
For just pure "Muppet" fun - The opening of the Harry Belafonte episode, where Fozzie tries to write the script for the show as the show is being performed... "Lagies and Genklefins..."